Liquid crystal optical device and process for its production

Abstract

To provide a liquid crystal optical device showing a low haze value in the transparent state, further an excellent stability in the transparent-scattering characteristics and productivity, and to provide a production process thereof. The liquid crystal optical device in the embodiment 1 of the present invention is a liquid crystal optical device 1 comprising a pair of insulating substrates 11 and 21 , of which at least one is transparent, electrodes 12 and 22 formed on respective inner faces of the substrates, and a composite 50 comprising nematic liquid crystal and a cured material, interposed between the inner faces of the substrates. The composite 50 is obtained by curing the following curable compound in the following chiral nematic liquid crystal composition in a state where the liquid crystal composition is interposed between the inner faces of the insulating substrates and the liquid crystal is aligned: chiral nematic liquid crystal composition: a liquid crystal composition showing a chiral nematic phase, comprising nematic liquid crystal and a curable compound, wherein at least a part of the curable compound is an optically active material having an optical rotatory power, and the optically active material having an optical rotatory power consists substantially solely of the curable compound.

1 . A liquid crystal optical device comprising:
 a pair of insulating substrates, of which at least one is transparent,   electrodes formed on respective inner faces of the insulating substrates, and   a composite of a nematic liquid crystal and a cured product, interposed between the inner faces of the insulating substrates, wherein:   the composite is obtained by curing the following curable compound in the following chiral nematic liquid crystal composition in a state where the liquid crystal composition is interposed between the inner faces of the insulating substrates and the liquid crystal is aligned:   chiral nematic liquid crystal composition: a liquid crystal composition comprising a nematic liquid crystal and a curable compound, and showing a chiral nematic phase, wherein at least a part of the curable compound is an optically active material having an optical rotatory power, and the optically active material having an optical rotatory power consists substantially solely of the curable compound.   
   
   
       2 . The liquid crystal optical device according to  claim 1 , which is obtained by curing the curable compound in a state where no voltage is applied to the electrodes. 
   
   
       3 . The liquid crystal optical device according to  claim 1 , wherein the curable compound is cured in a state where the chiral nematic liquid crystal composition is in focal conic alignment. 
   
   
       4 . The liquid crystal optical device according to  claim 1 , wherein the chiral nematic liquid crystal composition further contains a curable compound which is not an optically active material. 
   
   
       5 . The liquid crystal optical device according to  claim 1 , wherein the total amount of the curable compound is from 0.1 to 20 mass % based on the entire chiral nematic liquid crystal composition. 
   
   
       6 . The liquid crystal optical device according to  claim 1 , wherein the dielectric anisotropy of the chiral nematic liquid crystal composition is positive. 
   
   
       7 . A process for producing a liquid crystal optical device comprising a composite of nematic liquid crystal and a cured product, which comprises;
 a step of forming electrodes on inner faces of a pair of insulating substrates, of which at least one is transparent,   a step of bonding the insulating substrates so that the inner faces of the insulating substrates face each other via the following chiral nematic liquid crystal composition, and   a step of forming the composite by curing the curable compound in the liquid crystal composition in a state where the liquid crystal composition is interposed between the inner faces of the insulating substrates, and the liquid crystal is aligned:   Chiral nematic liquid crystal composition: a liquid crystal composition comprising a nematic liquid crystal and a curable compound, and showing a chiral nematic phase, wherein at least a part of the curable compound is an optically active material having an optical rotatory power, and the optically active material having an optical rotatory power consists substantially solely of the curable compound.   
   
   
       8 . The process for producing a liquid crystal optical device according to  claim 7 , wherein the curing of the curable compound is carried out in a state where no voltage is applied to the electrodes. 
   
   
       9 . The process for producing a liquid crystal optical device according to  claim 7 , wherein the curable compound is cured in a state where the chiral nematic liquid crystal composition is in focal conic alignment. 
   
   
       10 . The process for producing a liquid crystal optical device according to  claim 9 , wherein a voltage is applied to the chiral nematic liquid crystal composition for the focal conic alignment. 
   
   
       11 . The process for producing a liquid crystal optical device according to  claim 9 , wherein the chiral nematic liquid crystal composition is heated or cooled for the focal conic alignment.